The present invention relates generally to utilizing controlled transmissions of electromagnetic (EM) energy through or across non-magnetizable materials that have previously been barriers to penetration to determine the thickness and EM characteristics of materials.
It has long been possible to measure metallic thickness variations by electromagnetics. Prior methods have typically excited the metal by eddy currents or D.C. fields. After excitation, the known methods looked for variations in amplitude of the signal corresponding to variations in metallic thickness.
Additional features and advantages of the invention will be set forth in part in the description which follows, and in part will become apparent from the description, or may be learned by practice of the invention. The features and advantages of the invention may be realized by means of the combinations and steps particularly pointed out in the appended claims.
To achieve the foregoing objects, features, and advantages and in accordance with the purpose of the invention as embodied and broadly described herein, a method for the measurement of electrical properties of materials through non-magnetizable materials is provided. The method is also used to calculate the thickness of a material with unknown permeability and conductivity using transparencies. The method comprising the steps of creating a first set of electromagnetic waves having specific constant amplitude of a known frequency, the first set of electromagnetic waves for engaging a system, impinging the first set of electromagnetic waves on the system under investigation, nulling the system, receiving a nulled signal, creating a change in the system, and receiving a modified signal associated with the change from the nulled signal such that the modified signal contains sufficient information to determine the change in the system.
The method further comprising the steps of testing empirically to approximate the conductivity, testing empirically to approximate the permeability, creating a second set of electromagnetic waves adjacent to the system to be measured, the second set of electromagnetic waves being of a relatively low frequency and of lower frequency that the first set of electromagnetic waves, and impinging the second set of electromagnetic waves on the system for saturating a portion of the material in the system.